575 research outputs found
Thoraco-lumbar vertebral fractures with posterior wall retropulsion: room and importance for an effective minimally invasive treatment.
Functional Impairment, Illness Burden, and Depressive Symptoms in Older Adults: Does Type of Social Relationship Matter?
Objective: The nature of interpersonal relationships, whether supportive or critical, may affect the association between health status and mental health outcomes. We examined the potential moderating effects of social support, as a buffer, and family criticism, as an exacerbating factor, on the association between illness burden, functional impairment and depressive symptoms.
Methods: Our sample of 735 older adults, 65 years and older, was recruited from internal and family medicine primary care offices. Trained interviewers administered the Hamilton Rating Scale for Depression, Duke Social Support Inventory, and Family Emotional Involvement and Criticism Scale. Physician-rated assessments of health, including the Karnofsky Performance Status Scale and Cumulative Illness Rating Scale, were also completed.
Results: Linear multivariable hierarchical regression results indicate that social interaction was a significant buffer, weakening the association between illness burden and depressive symptoms, whereas perceived social support buffered the relationship between functional impairment and depressive symptoms. Family criticism and instrumental social support were not significant moderators.
Conclusions: Type of medical dysfunction, whether illness or impairment, may require different therapeutic and supportive approaches. Enhancement of perceived social support, for those who are impaired, and encouragement of social interactions, for those who are ill, may be important intervention targets for treatment of depressive symptoms in older adult primary care patients
On the Source of Energetic Electron Precipitation during Auroral Substorms
Precipitating auroral electrons are believed to originate mainly from parallel electric fields set up at the auroral acceleration region (AAR) extending up to 20,000 km altitude. However, electrons of energy greater than 100 keV are probably generated by acceleration processes beyond the AAR. Observational evidence for the source location of these energetic electrons are hard to come by. In our current work, we present simultaneous magnetically conjugate measurements of energetic electron spectra estimated at the ionosphere using the Poker Flat Incoherent Scatter Radar (PFISR) and measured at the inner plasma sheet by the THEMIS spacecraft. The flux of precipitating electrons of energy greater than 100 keV demonstrate a striking spatio-temporal correlation with that of the inner plasma sheet electrons. This suggests that the source of the energetic electrons lie at or beyond the inner plasma sheet, and that the acceleration processes within the auroral acceleration zone don't contribute substantially to their energization. Using simultaneous THEMIS measurements of wave power, we speculate that the electromagnetic ion cyclotron (EMIC) and Chorus waves are likely candidates for electron acceleration within the inner plasma sheet apart from the usual candidates of betatron and fermi
acceleration. However, between the ionosphere and the plasma sheet, electrons of energy less than 100 keV show significant differences in their energy spectra after the substorm onset suggesting an active AAR
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Comparison of the Efficacy of Caudal, Interlaminar, and Transforaminal Epidural Injections in Managing Lumbar Disc Herniation: Is One Method Superior to the Other?
Background: Epidural injections are performed utilizing 3 approaches in the lumbar spine: caudal, interlaminar, and transforaminal. The literature on the efficacy of epidural injections has been sporadic. There are few high-quality randomized trials performed under fluoroscopy in managing disc herniation that have a long-term follow-up and appropriate outcome parameters. There is also a lack of literature comparing the efficacy of these 3 approaches. Methods: This manuscript analyzes data from 3 randomized controlled trials that assessed a total of 360 patients with lumbar disc herniation. There were 120 patients per trial either receiving local anesthetic alone (60 patients) or local anesthetic with steroids (60 patients). Results: Analysis showed similar efficacy for caudal, interlaminar, and transforaminal approaches in managing chronic pain and disability from disc herniation. The analysis of caudal epidural injections showed the potential superiority of steroids compared with local anesthetic alone a 2-year follow-up, based on the average relief per procedure. In the interlaminar group, results were somewhat superior for pain relief in the steroid group at 6 months and functional status at 12 months. Interlaminar epidurals provided improvement in a significantly higher proportion of patients. The proportion of patients nonresponsive to initial injections was also lower in the group for local anesthetic with steroid in the interlaminar trial. Conclusions: The results of this assessment show significant improvement in patients suffering from chronic lumbar disc herniation with 3 lumbar epidural approaches with local anesthetic alone, or using steroids with long-term follow-up of up to 2 years, in a contemporary interventional pain management setting
Reconstruction of Fine Scale Auroral Dynamics
We present a feasibility study for a high frame rate, short baseline auroral tomographic imaging system useful for estimating parametric variations in the precipitating electron number flux spectrum of dynamic auroral events. Of particular interest are auroral substorms, characterized by spatial variations of order 100 m and temporal variations of order 10 ms. These scales are thought to be produced by dispersive Alfvén waves in the near-Earth magnetosphere. The auroral tomography system characterized in this paper reconstructs the auroral volume emission rate to estimate the characteristic energy and location in the direction perpendicular to the geomagnetic field of peak electron precipitation flux using a distributed network of precisely synchronized ground-based cameras. As the observing baseline decreases, the tomographic inverse problem becomes highly ill-conditioned; as the sampling rate increases, the signal-to-noise ratio degrades and synchronization requirements become increasingly critical. Our approach to these challenges uses a physics-based auroral model to regularize the poorly-observed vertical dimension. Specifically, the vertical dimension is expanded in a low-dimensional basis consisting of eigenprofiles computed over the range of expected energies in the precipitating electron flux, while the horizontal dimension retains a standard orthogonal pixel basis. Simulation results show typical characteristic energy estimation error less than 30% for a 3 km baseline achievable within the confines of the Poker Flat Research Range, using GPS-synchronized Electron Multiplying CCD cameras with broad-band BG3 optical filters that pass prompt auroral emissions.National Science Foundation Atmosphere and Geospace Directorate, Grants 1216530, 123737
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Retrospective cohort study of usage patterns of epidural injections for spinal pain in the US fee-for-service Medicare population from 2000 to 2014
Objective: To assess the usage patterns of epidural injections for chronic spinal pain in the fee-for-service (FFS) Medicare population from 2000 to 2014 in the USA. Design: A retrospective cohort. Methods: The descriptive analysis of the administrative database from Centers for Medicare and Medicaid Services (CMS) Physician/Supplier Procedure Summary (PSPS) master data from 2000 to 2014 was performed. The guidance from Strengthening the Reporting of Observational studies in Epidemiology (STROBE) was applied. Analysis included multiple variables based on the procedures, specialties and geography. Results: Overall epidural injections increased 99% per 100 000 Medicare beneficiaries with an annual increase of 5% from 2000 to 2014. Lumbar interlaminar and caudal epidural injections constituted 36.2% of all epidural injections, with an overall decrease of 2% and an annual decrease of 0.2% per 100 000 Medicare beneficiaries. However, lumbosacral transforaminal epidural injections increased 609% with an annual increase of 15% from 2000 to 2014 per 100 000 Medicare population. Conclusions: Usage of epidural injections increased from 2000 to 2014, with a decline thereafter. However, an escalating growth has been seen for lumbosacral transforaminal epidural injections despite numerous reports of complications and regulations to curb the usage of transforaminal epidural injections
The California-Kepler Survey V. Peas in a Pod: Planets in a Kepler Multi-planet System are Similar in Size and Regularly Spaced
We have established precise planet radii, semimajor axes, incident stellar
fluxes, and stellar masses for 909 planets in 355 multi-planet systems
discovered by Kepler. In this sample, we find that planets within a single
multi-planet system have correlated sizes: each planet is more likely to be the
size of its neighbor than a size drawn at random from the distribution of
observed planet sizes. In systems with three or more planets, the planets tend
to have a regular spacing: the orbital period ratios of adjacent pairs of
planets are correlated. Furthermore, the orbital period ratios are smaller in
systems with smaller planets, suggesting that the patterns in planet sizes and
spacing are linked through formation and/or subsequent orbital dynamics. Yet,
we find that essentially no planets have orbital period ratios smaller than
, regardless of planet size. Using empirical mass-radius relationships, we
estimate the mutual Hill separations of planet pairs. We find that of
the planet pairs are at least 10 mutual Hill radii apart, and that a spacing of
mutual Hill radii is most common. We also find that when comparing
planet sizes, the outer planet is larger in of cases, and the
typical ratio of the outer to inner planet size is positively correlated with
the temperature difference between the planets. This could be the result of
photo-evaporation.Comment: Published in The Astronomical Journal. 15 pages, 17 figure
The California-Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars
We present stellar and planetary properties for 1305 Kepler Objects of
Interest (KOIs) hosting 2025 planet candidates observed as part of the
California-Kepler Survey. We combine spectroscopic constraints, presented in
Paper I, with stellar interior modeling to estimate stellar masses, radii, and
ages. Stellar radii are typically constrained to 11%, compared to 40% when only
photometric constraints are used. Stellar masses are constrained to 4%, and
ages are constrained to 30%. We verify the integrity of the stellar parameters
through comparisons with asteroseismic studies and Gaia parallaxes. We also
recompute planetary radii for 2025 planet candidates. Because knowledge of
planetary radii is often limited by uncertainties in stellar size, we improve
the uncertainties in planet radii from typically 42% to 12%. We also leverage
improved knowledge of stellar effective temperature to recompute incident
stellar fluxes for the planets, now precise to 21%, compared to a factor of two
when derived from photometry.Comment: 13 pages, 4 figures, 4 tables, accepted for publication in AJ; full
versions of tables 3 and 4 are include
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